ABSURD

ABSURD (absurdus, irrational—logically contradictory).— What is contrary to
experience cannot be called absurd, for there may be facts and laws unknown to
us; but the self-contradictory is absurd. The reductio ad absurdum is a proof of
the irrationality of a position. It is at times adopted as a means of
establishing a proposition when the contradictory proposition is reduced to
absurdity.